1-Sample Proportion Test
Analyze PhaseTest whether an observed proportion (defect rate, pass rate, yield) is significantly different from a target or historical value. Uses the z-test for proportions.
Input Summary Statistics
Events, defects, passes, etc.
e.g. 0.20 for 20%
Observed: 23.5%Target: 20.0%
Blue bar = observed proportion. Vertical line = hypothesised proportion.
Hypotheses
H₀: p = p₀ = 20.0%
H₁: p ≠ p₀ (two-tailed)
No Significant Difference
z = 1.237, p = 0.2159 ≥ 0.05. Fail to reject H₀ — the observed proportion (23.5%) is not significantly different from 20.0%.
Test Statistics
n
200
Observed p̂
23.50%
Hypothesised p₀
20.00%
z-statistic
1.237
p-value
0.2159
95% CI Lower
17.62%
95% CI Upper
29.38%
Significant?
No
95% Confidence Interval for p
[17.62%, 29.38%]
The CI contains p₀ = 20.0% — consistent with H₀.